Verticalization of bacterial biofilms. Author Farzan Beroz, Jing Yan, Benedikt Sabass, Howard Stone, Bonnie Bassler, Ned Wingreen, Yigal Meir Publication Year 2018 Type Journal Article Abstract Biofilms are communities of bacteria adhered to surfaces. Recently, biofilms of rod-shaped bacteria were observed at single-cell resolution and shown to develop from a disordered, two-dimensional layer of founder cells into a three-dimensional structure with a vertically-aligned core. Here, we elucidate the physical mechanism underpinning this transition using a combination of agent-based and continuum modeling. We find that verticalization proceeds through a series of localized mechanical instabilities on the cellular scale. For short cells, these instabilities are primarily triggered by cell division, whereas long cells are more likely to be peeled off the surface by nearby vertical cells, creating an "inverse domino effect". The interplay between cell growth and cell verticalization gives rise to an exotic mechanical state in which the effective surface pressure becomes constant throughout the growing core of the biofilm surface layer. This dynamical isobaricity determines the expansion speed of a biofilm cluster and thereby governs how cells access the third dimension. In particular, theory predicts that a longer average cell length yields more rapidly expanding, flatter biofilms. We experimentally show that such changes in biofilm development occur by exploiting chemicals that modulate cell length. Journal Nat Phys Volume 14 Issue 9 Pages 954-960 Date Published 2018 Sep ISSN Number 1745-2473 DOI 10.1038/s41567-018-0170-4 Alternate Journal Nat Phys PMCID PMC6426328 PMID 30906420 PubMedPubMed CentralGoogle ScholarBibTeXEndNote X3 XML